drawbaugh



(No Model.) 2 Sheets-Sheet 1. D. DRAWIBAUGH.

PNEUMATIC TOOL.

No. 504,803. Patented Sept. 12, 1893.

mrIIIlIlIlII/I/m \IJIW D. DRAWBAUGH. PNEUMATIC TOOL.

(No Model.) 2 sheets-Sheena,

No. 504,808. 99 Patented Sept. 12, 1893'.

m a g y A q 1 fl/ q v fi s s 9 l ALL UNiTnD STATES PATENT Orricn.

DANIEL DRAIVBAUGH, OF EBERLYS MILL, PENNSYLVANIA, ASSIGNOR TO THE PNEUMATIC AND ELECTRIC TOOL COMPANY, OF NEW YORK, N. Y.

PN EU MATlC TOOL.

SPECIFICATION forming part of Letters Patent No. 504,803, dated September 12, 1893.

Application filed January 11, 1893. Serial No. 458,033. (No model.)

To aZZ whom it may concern: curately within the casing and at the upper Be it known that I, DANIEL DRAWBAUGH, end is formed into a head piece or cap I) for of Eberlys Mill,in the county of Cumberland the engagement of the air supply pipe, diand State of Pennsylvania, have invented cer-' rectly if desired, but preferably through the 55 tain new and useful Improvements in Pneumedium of the out off device shown and herematic Tools; and I do hereby declare the folinafter more specifically described. The caslowing to be a full, clear, and exact descriping and cylinder are preferably united by tion of the same, reference being had to the threading the base of the cylinder and the accompanying drawings, forming a part of corresponding end of the casing, which may 60 this specification, and to the letters of referbe thus slipped over the cylinder until the ence marked thereon. threads are brought together, and then a few This invention has for its object to provide turns suffice to hold them firmly in place. an improved pneumatic tool for stone cutting, No passages or ports for the air are formed in dressing, chipping, calking, repouss work, the casing, but the outer surface of the cyl- 6 &c., in which the working parts shall be siminder is channeled and by fitting accurately plified and the cost of production reduced, in the casing the channels are covered and while the power for a given size is increased the passages are completed as will be readily without the necessity of a proportionate inunderstood. crease in the working pressure,and at the same In the particular construction of tool shown, 20 time the length of the tool may be reduced-to straight channels 0, D, are formed on diasuit the workmans requirements for certain metrically opposite sides of the cylinder, the kinds of work. former C, communicating through the pas- The invention consists in certain novel desage O at the top with the induction or presstails of construction and combinations and are supply port and the latter through the 2 5 arrangements of parts all as will be now depassage D with the eduction or exhaust port scribed and pointed out particularly in the D At the lower ends of the channels C and appended claims. D ports or elongated openings 0 d, are formed Referring to the accompanying drawings: in the walls of the cylinder adapted to reg- Figure l is a partial section and elevation of ister at all times with a supply port 0 and 0 a tool embodying my present invention. Fig. exhaust port (1 respectively, located in the 2 is a similar viewlooking at the opposite side beater G and leading to the valve which conof the cylinder and with the outer casing retrols the distribution of the air to each end of moved. Fig. 3 is a vertical section taken on the cylinder thereby securing the reciprocathe line 50-50, Fig. 1 with the valve dotted. tions of the beater. This valve, unlike the 3 5 Figdisasection through the piston orbeater valve in tools heretofore patented to me, is at right angles to Fig. 3 with the valvein full located in the beater itself, and the ports and lines. Figs. 5, 6, '7, and 8 are views correpassages are so arranged that the momentum sponding to Figs. 1, 2, 3 and 4, but of a niodiof the valve assists materially in moving or tied form of tool. Fig. 9 is a cross section of shifting the same at the end of each stroke 40 the beater Fig. 4. to bring the proper ports into registry to Like letters of reference in the several figcause the reverse movement of the beater. ures indicate the same parts. In carrying this idea into practice, I do not In the preferred form of tool shown in Fig. depend entirely upon momentum to shift the 1, the casing including the cylinder, nose secvalve as has heretofore been proposed, nor 9 5 5 tion, and rear end, are formed in but two entirely upon the air pressure, but combine pieces, for which purpose, the outer casing or the two whereby a very certain action is seshell A is provided with a forward extension cured and an action which cannot be excelled or nose at which is bored for the reception of for speed, to say nothing of the fact that a the tool or tool stock, as the case may be, and full movement of the beater is insured. 50 at the rear end is cored out for the reception Referring particularly to Figs. 3 and 4 it of the cylinder proper B. The latter fits acwill be seen that the beater is bored out longitudinally to form a chamber for the valve E which may work directly in the said chamber, or in a separate casing forced into the chamber as in Figs. '7 and 8, and the end of the opening is closed by a plug F, preferably screw threaded, and provided with a projecting head adapted to enter a recess f in the end of the cylinder, to form an air cushion on the return stroke. The ports or passages c d, before referred to, are formed transversely in the walls of the heater and at points where they will register with the ports or openings 0 d, in the cylinder all the while. Passage 0 passes straight through the beater wall and terminates in a transversely elongated port it constituting the pressure supply port; and passage 01 is divided into two branches terminating in ports 9 g constituting the main exhaust ports.

In the walls of the beater, and preferably in the same transverse planes as the ports 9 g, are what I shall term the secondary exhaust ports, opening out respectively through passages g g at opposite ends of the beater, and adapted when brought into registry with the ports g g to exhaust the pressure from one end or the other of the cylinder as the case may be.

For the purpose of conveying pressure from the supply port to one end or the other of the cylinder, I locate secondary supply ports h h in planes between the pressure supply port it and the exhaust ports g and form passages 72, 7& leading respectively from said secondary supply ports out to the end of the heater for supplying pressure to the opposite ends of the cylinder. WVith this arrangement of ports the valve H need have but a single central annular recess H of proper length to connect the supply port It with one or the other of the secondary supply ports when at one or the other extreme of its movement. The exhaust port g and secondary exhaust port g at the opposite end of the beater are brought into communication by the valve moving entirely beyond them as shown clearly in Figs.

3 and 4. When the valve is at the lower end of its chest, the lower secondary supply port is in communication with the pressure supply port, and vice versa. Hence as the beater is arrested at the end of its stroke, the valve tends to continue its movement, by momentum, independently of the heater and opens the opposite ports to cause the reverse movement of the beater, and to assist this movement of the valve, and more especially to inaugurate it, if anything, before the beater reaches the end of its stroke, the beater is provided with small ports 1' i and 'i 11' at each end, passing into the valve chest at the end and through to the outside of the beater when they are adapted to register with ports 2' 1' or d i opening through the cylinder into the pressure or exhaust channels.

One or the other of the ports 2' 2' registers with ports 2' t leading to the pressure passage, as the beater reaches one or the other of its extremes of movement, the ports being preferably arranged to be full open just as the movement of the heater is arrested, and the one or the other of the ports t" 2" located at the opposite end of the beater, simultaneously registers with one or the other of the ports i 2 serving to simultaneously exhaust the pressure from that end of the valve. By thus moving the valve in both directions by the combined action of the compressed air and momentum, an action is secured which is exceedingly quick and by arranging difierent ports and passages for the entry and exhaust to each end of the cylinder I am enabled to reduce the movement of the valve to the minimum and at the same time secure the advantages of a wide head to effect the cutting 01f and a rapid and complete opening of the ports, whereby the pressure is instantly exerted in the cylinder without being throttled in the least in passing through the ports and passages. The ports in the valve chamber it will be noted are elongated transversely as shown in Fig. 9, and are formed by a rotary cutter introduced from the end of the chamber, while the passages communicating therewith are bored from the outside of the beater, which process not only enables me to form ports and passages having finished edges on both sides, but perfect accuracy in the location of the ports is secured with the advantage of a long narrow port inside and a circular passage of large capacity communicating therewith.

To form the lower end or head of the cylinder, a washer J is seated in the casing and held tightly in place by the lower end of the cylinder, and in a bearing in this washer is journaled to move longitudinally the reduced shankj of the button j, the head of which works in a cavityj in the nose of the casing and is adapted to bear against the head or stock of the tool and impart the impact of the beater thereto, thus securing the advantages of having a cylinder closed at the bottom against the escape of pressure, coupled with the advantage of a beater acting directly on the tool. The button is of such light weight as to practically give the same effect as though the tool were struck directly.

To govern the entry of air to the tool I now provide a cut-off which is preferably connected with and forms part of the tool itself. Thus by reference to the drawings it will be seen that the rear end of the tool is bored out for the reception of a short section of tube or a cylinderK, the rear end of which is threaded or otherwise formed for the attachment of the supply pipe, while its inner end is provided with an aperture K adapted to register when desired with the corresponding passage in the tool constituting the supply passage. Thus, by turning the tube one way or the other, the apertures may be caused to register, or be moved out of alignment, to cut off the supply to a greater or less extent. The tube is preferably provided with an annular flange held within the end of the tool by any suitable means, such for instance as by having the tube inserted from the inside as in Figs. 4 to 8 or by a nut as in Figs. 1 to 4, and on the outer end of the tube I mount a collar Ii preferably knurled on the outside and fastened by a set screw for the sake of adjustability. This collar serves as a ready means for turning the tube and itmay also serve as a carrier for a spring pin Z which, co-operating with recessed corrugations Z in the head of the tool holds the tube in adjusted position and limits its movement in either direction;

Referring now to Figs. 4 to 8 it will be seen that this form of tool is made in four pieces, a point or nose section M, a cylinder M, a casing M and a head or cap section M The cylinder screws into the nose section and holds a washer and button in place just as before described, but the casing is slipped on from the upper end and abuts against an enlargement m at the lower end. The cap or head screws onto the upper end of the cylin der and holds the casing securely in place, in addition to which, a set screw m may be employed if desired. The supply and exhaust channels and ports are formed in the cylinder just as before described, and the heater is similar, so far as the pressure supply and exhaust passages, and the passages leading to and from the ends of the valve are concerned, but the ports for distributing the pressure and the construction of the valve are modified as follows:

Instead of forming the ports directly in the body of the beater, I bore said beater for the reception of a lining or valve casing N in which the ports are formed before insertion. Hence it is onlynecessary to form the supply and exhaust passages to register with the ports on the outside and that degree of accuracy necessary in forming the former beater is not required as the accuracy is secured in the formation of the valve casing.

If reference be had to my prior patent, No. 472,:t95, dated April 5, 1892, an arrangement of valve, valve casing and ports will be seen similar to the present, the diiference being that in said prior tool the valve and its casing are located in the main casing instead of in the beater and hence required special and complicated borings in the walls of the casing for the air passages, which in the present arrangement, are entirely dispensed with.

In operation the air pressure is constant at the ports 19 p, and port 1) is constantly open to exhaust, while ports 13 p open through passages 13 p to opposite ends of the beater respectively. The valve 0 has two annular chambers o oadapted to connect the ports p 13 respectively with either the supply port at that end, or the central exhaust port, depending upon the longitudinal position of the valve. The movement of the valve it will be observed, is timed similar to that of the valve first described so as to take advantage of the momentum acquired by the movement of the beater to assist in shifting the valve. Thus when the valve is at one end of its chamber the ports are connected for moving the beater in the opposite direction, and vice versa.

The part which I have termed a button, for transmitting the impact of the beater to the tool, it will be observed, fits snugly in its bearing in the washer so as to prevent the escape of air, inasmuch as the said button serves as a closure for the lower end of the cylinder. This structure simplifies the manufacture of the tool considerably, and enables me to secure the advantages of a beater acting directly on the tool, as before stated, without the disadvantage incident to the construction of a beater with a projection or nose, or when special provision must be made to introduce pressure beneath some small part or reduced area of the beater to secure the back or reverse stroke.

By arranging the valve in the beater to work in the same direction, a material advantage is gained in this class of tool which is adapted to be held in the hand, for not only is lateral vibration entirely overcome but the vibration of the valve is practically unfelt being absorbed entirely in the movement of the beater and by arranging the ports to cut off on the return stroke the air cushion will practically neutralize all evil effects from the back stroke of the beater and valve.

Having thus described my invention, what I claim as new is- 1. In a pneumatic tool adapted to be held in the operators hand, the combination with the cylinder having pressure supply and exhaust passages and the loose beater reciprocating therein having pressure supply and exhaust passages registering with those in the cylinder, and independent secondary supply and exhaust passages leading to each of its ends, of a valve working in said heater and operating to connectthe main and secondary supply passages and main and secondary exhaust passages, simultaneously, at opposite ends of the beater; substantially as described.

2. In a pneumatic tool adapted to be held in the operators hand, the combination with the cylinder having pressure supply and exhaust passages, and the loose beater reciproeating therein having pressure supply and exhaust passages registering with those in the cylinder and independent secondary supply and exhaust passages leading to each of its ends, of a valve working in said beater having a single central annular chamber for connecting the main and secondary supply passages at each end alternately, and simultaneously putting the opposite main and secondary exhaust passages into communication across the end of the valve; substantially as described.

3. In a pneumatic tool adapted to be held in the operators hand, the combination with the cylinder having pressure supply and exhaust passages and the loose beater reciprocating therein having pressure supply and exhaust passages registering with those in the cylinder, and independent secondary pressure supply and exhaust passages leading to each of its ends, a central valve chamber with which said passages communicate and small passages, for supplying pressure to each end of said valve chamber to move the valve, controlled by the longitudinal movement of the beater, of a valve working in said chamber for alternately opening communication between the main and secondary pressure supply passages and main and secondary exhaust passages at each end of the beater; substantially as described.

- 4. In a pneumatic tool, the combination with the cylinder having the end recessed to form a cushion chamber, of the beater bored longitudinally to form a valve chamber and a plug closing the end of said chamber having a projecting head adapted to enter the recess in the end of the cylinder substantially as described.

5. In a pneumatic tool, the combination with the cylinder having the end recessed to form a cushion chamber, the beater working therein and bored longitudinally toform a central valve chamber and with supply and exhaust passages in the wall around said chamber, of the valve working in the valve chamber and the screw plug fitting in the end of the chamber to close the same and having the projecting head for entering the recess in the end of the cylinder to form a cushion; substantially as described.

6. In a pneumatic tool, the combination with the cylinder having pressure supply and exhaust passages with ports for supplying pressure to and exhausting pressure from the ends of the valve, of the beater bored longitudinally to form a valve chamber and having lateral passages leading from each end of said chamber and registering at opposite extremes of the movement of the beater with the said valve supply and exhaust passages respectively, and a valve working in said chamber and controlling the supply and exhausting of pressure from opposite ends of the beater; substantially as described.

7. In a pneumatic tool, the combination with the cylinder having the nose section bored out to form a tool holder and a beater working in the cylinder, of the washer at the lower end of the cylinder and the button working through a bearing in said washer to form a closure for the end of the cylinder and adapted to receive the blows of the beater and transmit the same to the tool held loosely in the nose section; substantially as described.

8. In a pneumatic tool, the combination with the cylinder having the nose section bored out and forming a tool holder and the beater working in said cylinder, of the button constituting the closure for the lower end of the cylinder and upper end of the tool holder, and having a limited longitudinal movement whereby the blows of the beater delivered thereon are transmitted to the tool; substantially as described.

9. In a pneumatic tool, the combination with the cylinder having the beater working therein and the pressure supply and exhaust channels formed in its exterior, of the casing fitting over said cylinder to inclose the channels and form passages, and the nose section formed integral with said casing at the lower end; substantially as described.

10. In a pneumatic tool, the combination with the cylinder having the head section formed integral therewith the channels in the exterior of the cylinder and the beater working in said cylinder, of the casing inclosing the cylinder and united thereto by a screw thread at the base of the cylinder, and the point section formed integral with said casing and bored out to form a tool holder; substantially as-described.

11. In a pneumatic tool, the combination with cylinder or casing having the pressure supply passage and the beater reciprocating within the cylinder, of the cut-01f tube journaled to rotate in the rear end of the tool and having the aperture registering with the supply passage in the tool at one end, and with the opposite end formed for the attachment of the supply pipe; substantially as described.

12. In a pneumatic tool, the combination with the cylinder or casing having the press ure supply passage, the cylindrical opening into which said passage opens and the beater, ot' the cut off tube journaled to rotate in said cylindrical opening and having an aperture adapted to register with the supply passage in the tool and the collar on the outer end of the tube for turning the same; substantially as described.

13. In a pneumatic tool, the combination with the cylinder or casing having the beater and supply passage terminating in a cylin drical opening at the rear end of the tool, of the cut-off tube journaled in said cylindrical opening and having the annular enlargement held within the tool and the collar secured on the outer end of the tube for turning the same; substantially as described.

DANIEL DRAWBAUGH.

WVitnesses:

R. S. CARE, D. S. SEITZ. 

